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Bachmann/Farish Castle Class front bogie derails on points


Gremlin
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I have some curved points and the front bogie on locomotive usually derails as it passes over them.  Have replaced the points several times, but no improvement :(

 

Should I consider adding weight on the bogie (somehow?) or a spring or...?

 

Cheers

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I would suggest getting a back to back gauge and checking the bogie wheel spacing before doing anything else, it can sometimes be incorrect even on new locos. They are available from DCC Concepts. 

 

What make and radius are the points? 

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5 hours ago, Gremlin said:

I have some curved points...

RTR curved points are typically very marginal devices. My experience is mostly in OO, but geometry is equally unforgiving in any gauge and scale. In order to produce enough divergence in a relatively short distance to make a feasible track piece, there is usually some element with tighter radius than 'advertised' as the overall smallest substitution radius within such a point. The end effect is that some vehicles which perform perfectly on plain track of the same radius as that advertised as the point's minimum radius, will bind and derail on the point.

 

A Castle has those awkward cylinders just where the rear bogie wheel wants to go on a small radius curve. Try moving the loco dead slow through the point, (perhaps by your finger pushing the tender) and watch those bogie wheels. If they stop turning, there's the trouble, and derailment will probably occur shortly after you see that. If the wheelsets are correct to gauge, then you have hit a limit. Checking that there isn't constraint to flexibility by the loco to tender coupling, carving away whatever fouled the wheels, fitting replacement smaller or finer profile wheelsets, may provide a solution. Or it may just have to be route restriction: the Castle cannot take this route.

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Apart from putting the thread under the wrong manufacturer - A Farish Castle is nothing to do with Dapol - you haven't said which curved points you are using.

 

I use the Peco SETRACK curved points and have issues with a lot of locos.  I find that not a lot of locos will run through them reliably in the facing direction - and this is regardless of manufacturer- Farish A2s and A1s and Dapol A3s and A4s all have problems.  Significantly none of my continental stock has any issue with these points- even propelling coaches at speed.

 

However, in a TRAILING direction they are fine and very useful space savers in a fiddle yard.  I have no issues with any locos of any make in this direction- trailing through ANY point is much kinder to stock than running in a facing direction.  Likewise the rake of Etched Pixels push-pull coaches runs through in a trailing direction with the G5 on the back- and runs through every time.

 

Les

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31 minutes ago, Les1952 said:

trailing through ANY point is much kinder to stock than running in a facing direction. 

Which is why real railways use facing point locks wherever traffic traverses facing points at speed, or carries passengers.

 

1 hour ago, 34theletterbetweenB&D said:

A Castle has those awkward cylinders just where the rear bogie wheel wants to go on a small radius curve

Which is why Churchward adopted the de Glehn 4 cylinder layout where the inside cylinders drive the leading axle and the outside ones the centre axle for the Stars, from which the Castles were developed.  The frames are jiggled out a step just in front of the outside cylinders so that there is more room for the inside ones, also the reason for the outside framed front axle of the King.  Model railway curvature, especially with setrack, is much smaller radius than anything a real Castle was expected to deal with, and compromises are inevitable if our models, with overscale flanges, are to run at all.  In 00 the incorrect narrow gauge gives a little leeway as well, but leads to problems with the cylinder sitting too far in if the connecting rod is to sit the correct distance out along the crankpin.  The usual compromise with cylinders is to cut a rebate away from the inside face of the cylinder moulding at the front, so that the flanges can clear them, but in 2mm this will only gain you about 0.25mm or so, if that.  It might do the trick, though.  It is also particularly visible on a loco with the de Glehn layout (Star, Castle, King, Princess, Duchess) because the outside cylinders are set so far back; on most other locos it is at least partially hidden by the buffer beam. 

 

Check the back to backs, and make sure the flangeways of your turnout are clear of debris.  I use a pound shop child's paintbrush with stiff nylon bristles for this; it's u/s for painting with!  Also, check that the turnout is laid level and smooth to it's adjoining pieces; put a straight edge over it and shine a light from behind.  

 

I have (in 00) a Hornby 4th-3rd radius curved turnout on my layout, at the fiddle yard entrance where it's space saving qualities are much appreciated.  But it is the root of some 99.9 recurring % of my running problems, and stock has to be set up to run over it in both directions, hauled and propelled, before it passes it's running trials; if it can negotiate this, nothing else on my railway will bother it.  It is also the test piece for loco pickup performance.  This is a problem of my own making, a compromise after I'd set the minimum radius as 4th in fiddle yard and Peco small for turnouts, but then shoehorned another 3 fiddle yard roads in...

 

Good luck with it and let us know how you get on!

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Thanks to everyone for the suggestions.  I am using Kato Unitrack N Gauge and have about 25m running in a double-U layout; there are a mixture of Dapol and Bachmann/Farish locos and, after realising that I had posted this in the wrong forum, I also tested assorted Dapol locos and achieved the same result :(

 

The turnout is a Kato #4 and the traffic is running FACING (not shouting...), I tried using several spare turnouts and the result was the same.  I also used several "Y" turnouts and the result was the same.  I have about eight other #4 turnouts where the same locos traverse them FACING with no problems.  The section of track is level and the traffic all follows the curved path and is integrated into a curved section of track (similar to other locations).

 

Eventually, I replaced the turnouts with a #6 and the locomotives now pass over it without fault.  They also pass over two other sections that are identical but use #4 turnouts.  I have a solution, but without clearly understanding the cause... as I noted, the #4 works perfectly in eight other locations, so... ?

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The Kato no.4 has quite tight clearances, I had to run a file between the frog and check rail to reduce the width of the check rail otherwise an old style Farish Pannier stuck fast, the flange and the pick ups getting trapped. May be a slight manufacturing issue that some are tighter in clearances than others or it might be to do with the approach angle to the point.

Edited by Butler Henderson
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Kato don't make curved points.

The #4 points are very problematic. The #6 points are much more likely to pass stock without problems.

Continental European stock is, in my experience, less likely to derail than British stock whatever the type of track.

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I did notice when running US outline on Kato track that certain locos by Atlas (and Kato!) tended to split Kato #4 points- particularly the RS3 and GP20 by Atlas and the PA from Kato.  I took the first RS3 back to M G Sharp from whence it came and it split the points on their Kato Unitrack test track - as did another one straight out of the box.  I ended up keeping the RS3 and changing over to Peco track.....

 

Later on, building the tramway on Furtwangen Ost I decided to go for Tomix Finetrack, which is much more forgiving than Unitrack.

 

From Kato I now only use their wires and turnout switches - the wires allow me a connector that can't be mistaken for a different one, and the switches work well mounted on the backscene if used with Tomix point motors...

 

Les

Edited by Les1952
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